Field of the Invention
One or more embodiments of the present invention relate to a white balance adjustment method for displaying an infrared light image and an RGB image simultaneously.
Background Art
In recent years, it has become possible to navigate surgery, specifically, identify blood flow before and after blood vessel surgery, identify lymph flow before and after lymphatic vessel surgery, and identify a position of a lymph node in cancer surgery, by employing indocyanine green which has been used as a test agent in hepatic function tests. This is achieved by capturing near-infrared fluorescence of 830-870 nm which is emitted from indocyanine green irradiated with infrared rays of 780 nm. Because near-infrared light of this band has relatively high transmission through living tissues, and thus observation from the skin or the surface of the organs becomes possible, it is an advantageous method.
As a camera system using a similar type of near-infrared light is desired to be applied to endoscopes, there is no doubt that the camera system will be developed and applied to endoscopes in the future. Furthermore, the camera system is also expected to be applied to, for example, microscopes.
Already-marketed endoscope systems for capturing near-infrared fluorescence do not have sufficient specifications for surgery navigation in that an image is monochrome and an image obtained by light other than near-infrared light is unclear. Further, although a high resolution camera is required for identifying, for example, minute cancer tissue, such a camera does not exist yet.
A camera system that can simultaneously capture near-infrared fluorescence and a color image has been achieved by employing a special color filter and a sensor adopting a special image processing technique. Further, the same result can be achieved by capturing a near-infrared image and a visible light color image separately and superimposing them in subsequent processing. However, in order to develop a high resolution camera system in the future, a vast number of man-hours are required as it is necessary to develop a special sensor dedicated to the camera system and provide a system employing a plurality of sensors to superimpose images.
It is desired to provide a camera system which can be realized with a single sensor and no special color filter, and which can capture a near-infrared image and a color image simultaneously in real time without requiring superimposition processing at a subsequent stage.